<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <link rel="stylesheet" href="./index.css">
  <style>
    * {
      margin-right: 0;
      padding: 0;
    }

    html body {
      width: 100%;
      height: 100%;
    }

    .con {
      width: 100%;
      height: 4000px;
      background: #ccc
    }

    .opticy_ {}
  </style>
</head>

<body>
  <div class="con">;
    <div class="opticy_"></div>

  </div>
</body>

</html>